While nanoparticle (NP) diffusion in polymer melts is important to the fabrication and applications of polymer nanocomposites, the influence of the NP/polymer interaction is poorly understood. Investigation of the weak NP/polymer interactions is experimentally challenging tendency for nanoparticle aggregation. Here, the diffusion coefficients of weakly attracting (methyl capped, CH3 QDs) and strongly attracting (carboxylic acid capped, COOH QDs) nanoparticles (radius ~ 6.5 nm) in poly(propylene glycol) (PPG) melts were measured by single particle tracking (SPT). The mean-squared displacements and van Hove distribution of nanoparticle motion show Brownian motion of non-aggregated nanoparticle, in the long-time diffusion regime (~1s). For weakly interacting CH3 QDs, the effective nanoparticle radius is independent of PPG MW due to the absence of a bound layer. For strongly interacting COOH QDs, the effective radius of the nanoparticle increases with the PPG molecular weight as MW0.5, indicating a long-lived bound layer. By obtaining spatial and temporal diffusion behavior of single nanoparticles, SPT provides previously inaccessible information on the nanoparticle diffusion in polymer melts.

Single particle tracking of sticky and non-sticky nanoparticles in polymer melts

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.